Pump stroke changing means



Spt. so, 1941] I G. B'RQWN 2 428,140 J PUMP STROKE CHANGING MEANS Filed Oct. 27, 1943 2 sheets-sheen Fiqrl.

Invenlor GA F/aa finowu B 5 K'ttoEneg.

Sept. 30, 1947. 3; BROWN I PUMP STROKE CHANGiNG MEANS 7 Filed Oct. 27, 1943 2 Sheets-Sheet 2 Patented Sept. 30, 1947 UNITED STATES PATENT OFFICE PUMP STROKE CHANGING MEANS Garfield Brown, Minneapolis, Minn, assignor to The Northern Pump Company, Minneapolis, Minn., a corporation of Minnesota Application October 27, 1943, Serial No. 507,828

i 4 Claims.

This invention. relates to a pump of the swash plate type and particularly to a novel mechanism for changing the stroke of said pump.

Said type of pump comprises a tilting plate which is mounted for swinging movement about trunnions at opposite sides thereof. This plate forms or carries what is called a swash plate to which one end of the piston rods are secured. The plate is given an oscillating or gyrating motion to give movement to the piston rods and pistons and the amount of piston travel can be varied by swinging said plate about said trunnions.

In this type of pump high pressures are commonly used and in the rotation of the tilting and swash plate the pistons are at the intake side of the cylinder for part of a revolution and at the discharge side of the cylinder for the other part of the revolution. This reversal of pressure places great stresses upon the tilting plate and upon any mechanism which is provided for swinging it. Such a mechanism must be capable of easy and small movement and must be constructed to withstand the pounding which it necessarily takes in the operation of the pump.

It is an object of this invention therefore to provide a simple and efficient mechanism for varying the stroke of a swash plate type of pump.

It is a further object of the invention to provide a member preferably in the form of a fork secured to the tilting plate between the trunnions thereof, a pin secured in and extending between the arms of said fork and a member connected-to said pin by movable connection and being movable about a longitudinal axis extending at right angles to the axis of the trunnions of the tilting plate, together with means for moving said member to swing said tilting plate. I

It is more specifically an object of the invention to provide a tilting plate swingable about trunnions at opposite sides thereof, a fork secured to and projecting from said plate, a pin secured in and extending between the arms of said fork, a plunger movable longitudinally in a direction at right angles to the axis of said trunnions, said plunger having a member movable therein and carried by said pin and means for moving said plunger to swing said fork'and said tilting plate.

' It is still further an object of the invention to provide such a structure as above set forth to"- gether with a casing enclosing the tilting plate,"

having an opening through which said fork pro-'- jects and a second casing secured to said casing and enclosing said fork and'a portion of said invention will be fully set forth in the following description made in connectionwith the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a view in horizontal section taken on line II of Fig. 2 as indicated by the arrows;

Fig. 2 is a vertical section taken on line 2-2 of Fig. 1 as indicated by the arrows;

Fig. 3 is a partial view in side elevation of a plunger used;

Fig. 4 is a vertical section taken on line 44 of Fig. 5 and Fig. 5 is a view in side elevation.

Referring to the drawings a portion of a pump of the swash plate type is shown comprising the tilting plate I0 which is swingable about the axis of trunnions Illa. A pump of the type referred to is shown in the patent'to John B. Hawley, Jr, et al. #2,307,041, granted January 5, 1943. Plate Ill has a boss lflb at one side between the trunnions thereof and a member II is secured to boss IIlb by the headed bolts I2. Member II is in the form of a fork and has projecting parallel arms Il a. A pin I3 is secured in and extends between arms I la, said pin being secured in any suitable manner as by one or more screws I4. The other end of pin I3 is flanged to hold it from endwise movement and is tapped to facilitate assembly and disassembly. Member I6 embraces pin l3 being journalled thereon and in the embodiment of the invention illustrated member I6 is provided with a cylindrical periphery as shown in Fig. l. Member I6 is also fitted for sliding movement in a bore Illa in an enlarged portion I8b of a shaft or plunger I8. Portion I8b is provided with elongated openings I at opposite sides which extend from its exterior into bore Isa. Pin I3 passes through the openings I80 and thus passes through member I8 which is disposed between arms Ila. Portion I8?) is provided with fiat sides I8d which extend parallel to the inner sides of arms Ila, it being noted that there is some'clearance between sides I861 and the inner sides or arms IIa. Plunger I8 extends some distance at either side of portion I8?) and is of cylindrical form fitting in bores in casings 20 and 2I. Casings 20 and 2| have chambers therein to which liquid may be supplied through openings 22a in cap members 23 secured to casings 2B and H respectively by bolts 24. A pipe 25 is connected to one member 23 a d a pipe 26 is connected to the other member .23. Members 23 engage suitable gaskets 21 in casings 20 and 2I to insure a tight seal. .Pipes 25 and 26, will be connected tov some suitable source of fluidtunder pressure so that fiuid'canbe applied to one end of member.

As shown in Fig. 4 the ends of member I 8 are pro 3 vided with bores IBe. The casings 20 and El are provided with cylindrical flanges 20a and 2Ia respectively which; are secured to-the; ends-:of the casing 30 by circumferentially spacedbolts 31-. it suitable gasket 32 is disposed between said flanges and casing 39 to insure a liquid-tight fit and lock;

washers 33 are shown as disposed beneath the heads of bolts 3|. with a base flange 30a and this is secured by spaced headed screws 35 tothe pump'casing 35:

which encloses tilting plate II) and the pump piste tons and other parts. Casingtli is providedwith. an opening 36a through which boss lllhandfork Ii extend. Lock washers 31 are shown as-disposed beneath the headset bolts 35, which heads are countersunk. in: flange 30m Casing 39" has bosses 30b at opposite sidesrprovided withxbores 300 which are axially alignedwith pin I3. Pin I3 canthusbe passed throughtoneof the openings 3flcfor assembly or disassembly. Coverplates 39 are secured to the outer sides of? bosses 36b over. the bores or openings 30cby circumferentially spaced headed screws 40, having their heads countersunk intoplates '39 and also having-lock washers 4 I beneath their heads.

Referring again: to pin I3=it is pointedout that there is an appreciable clearance between said pin and member I8- where said pin passes throughthe latter. This clearance permits movement ofmember I8 about-the axis of member. 1.6.

The top of. casing '30 is bored; and. tapped asshown at 36d to receive a plug (not shown).

In operation when it is desired to. change the stroke of the pump by swinging platelliabout its. trunnions, fluid. will be supplied through one of the pipes 25- or 7.6 and this will pass into the chamber of casing 20 or 2 1. This-fluid will move plunger I8 longitudinally, moving member Hi and thus moving fork II andSWinging plate I01. Asfork I I thus moves about the axis ofthe trunnions of plate Ill'..member.or-bl'ock IE will move downwardinmember I8; pin- I3 moving. inopenings lac. The-plunger. I8 will bemoved in one direction to increase the stroke of. the pump and will be movedin the other direction to decrease the stroke. It will be held in the desired position by the presence of. 'fluid, in chambers 20 and 2L It will be noted that the mechanism. provides movement, about three axes. Relative movement of member I8 about the axis of pin [3is provided. Relative movement of member I8 about the axis of pin I6 is possible and member I8 can turn to some extent about its own axis. This'gives a complete universal. motion between the operating member I8 and the plate. I to. be tilted; With this complete universal action of the connection or joint accurate alignment of the'parts is not necessary, but at the same timeany movement of member I8 is transmitted immediately to the tilting plate or box I0 with a minimum of lost motion. This is a great advantage in this structure of mechanism.

From the above description-it will beseen that I have provided a simple andyet very efiicient mechanism for adjusting the strok'e-ofa pump.

The connection between member I8 and fork II comprises nicely fitted partswith fairly large surfaces and these parts can move. easily relatively toeach other. As stated, the mechanism provides a complete universal motion. These. pumps are usually usedto pump oil and this oil can flow from the pump casing 36 through opening 3ta into casing 30 so that theouter'portion of the fork and members I6 and I8'will be thoroughly lubricated. The mechanism is very 'compactand 75,.

Casing 30 is aiso provided definedin'theappendedclaims.

4 the tilting plate can be easily and accurately moved small distances and as stated, with a minimum :of; lost motion. The massof the tiltin plateis large and' thezmechanism for: swinging it must be rugged and at the same time quite accurate. As above stated, the mechanism receives severe shocks in the operation of the pump and must be made very rugged to withstand such shocks. With the present; construction the tilting plate can be easily moved in either direction as desired The invention has'been amply demonstrated in actual practice and found to be very successful and' efiicient.

It: will. of course, be understood that various changes may be made in the form, details, arrangement and. proportions of. the parts, without departing from the scope of appli'cants invention, which generally stated. consists in" a device capable of carrying out the objects above setifortli, in the parts and combination of parts disclosed and What is claimed is z.

1. A device for changingthe stroke on a, swash plate pump having a; tilting plate swingableabout trunnions at its" opposite sides and a shaft with means for moving the same 'axially'at right angles to the axis of said trunnions, having in combination, a fork secured tosaid plate' at one side thereof and projecting substantially radially therefrom, a pin extending between and secured in the-armsof saidfork, a member journalled on said pin and having a periphery disposed about an axis at right angles-to said pin, said shaft extending between the armsof said fork andhavin an opening therein-in whichsaid member fits and is movable. at rig-ht angles to theaxisof said pin..

2; The structure set forth in claim I said shaft havingelongated openings therethrough through which said pin extends, sa-id pin moving in said openingsin the. movement of said member.

3. A: devicefor changing the stroke on a'swash plate pump having a tilting plate swingable about trunnions at its: opposite sides and a shaft with means. for moving. the same axially at right anglesto. the axis of said trunnions, having in combination, a-member secured to said plate, projecting. substantially radially at oneside thereof and having 'spacedarms, a: pin extending between and secured in saidarms, thesame extending parallel to the axis of said trunnions, and a. member journalled on said .pin and having a cylindrical periphery extending about an axis atv right: angles to said pin, said shaft having an opening therein in which said cylindrical periphery of said member fitsand is movable at right angles to the axis ofv said pin, said pin extending transverselythrough said shaft.

4. A device for changing the stroke on. a swash plate pump having a tilting'plate about trunnions at its-opposite sides and a, shaft adjacent said plate with means for moving the same axially at right angles to the axis of said trunnions, having.

in combination, afork secured to said plate and projecting radially from the periphery thereofsubstantially midway between said trunnions, a

pin extending between and secured against rota-- tion in the-arms of said fork, said'pin extending parallel. to the axis of said trunnions, and a member journaledon said: pin andhaving a cylindrical periphery extending about an axis at right angles to'the. axis of said pin and of much larger diameter than said pin, said' shaft extending between saidarms, said cylindrical periphery of said member fitting in anopening'insaid shaft, said memo-7 5 o 6 her being axially movable in said opening at right angles to the axis of said pin. UNITED STATES PATENTS GARFIELD BROWN Number Name Date 1,785,733 Francis Dec. 23,1930 REFERENCES CITED 5 1,924,749 McAvinney Sept. 25, 1934 The following references are of record in the 2,258,127 Almen Oct. 7, 1941 file of this patent:

2,341,768 Gonduk Feb. 15, 1944 

